Hi all, I'm capturing a photo using AVCapturePhotoOutput, and I've set: let photoSettings = AVCapturePhotoSettings() photoSettings.isDepthDataDeliveryEnabled = true Then I create the handler like this: let data = photo.fileDataRepresentation() let handler = try ImageRequestHandler(data: data, orientation: .right) Now I’m wondering: If depth data delivery is enabled, is it actually included and used when I pass the Data to ImageRequestHandler? Or do I need to explicitly pass the depth data using the other initializer? let handler = try ImageRequestHandler( cvPixelBuffer: photo.pixelBuffer!, depthData: photo.depthData, orientation: .right ) In short: Does ImageRequestHandler(data:) make use of embedded depth info from AVCapturePhoto.fileDataRepresentation() — or is the pixel buffer + explicit depth data required? Thanks for any clarification!

We have suddenly encountered a serious issue: our local ML models are no longer being decrypted. Everything was set up according to the guide at https://aninterestingwebsite.com/documentation/coreml/generating-a-model-encryption-key and had been working in production, but yesterday we started receiving the following error: Error Domain=com.apple.CoreML Code=8 "Fetching decryption key from server failed: noEntryFound("No records found"). Make sure the encryption key was generated with correct team ID." UserInfo={NSLocalizedDescription=Fetching decryption key from server failed: noEntryFound("No records found"). Make sure the encryption key was generated with correct team ID.} We haven’t changed anything in our code. This started spontaneously affecting users of the release version as of yesterday. It also no longer works locally — we receive the same error at the moment the autogenerated function is called: class func load(configuration: MLModelConfiguration = MLModelConfiguration(), completionHandler handler: @escaping (Swift.Result<ZingPDModel, Error>) -> Void) I assume that I can generate a new key through Xcode, integrate it in place of the old one, and it might start working again. However, this won’t affect existing users until they update the app. Could the issue be on Apple’s infrastructure side?

Greetings, and Happy Holidays, I've been building an on-device AI safety layer called Newton Engine, designed to validate prompts before they reach FoundationModels (or any LLM). Wanted to share v1.3 and get feedback from the community. The Problem Current AI safety is post-training — baked into the model, probabilistic, not auditable. When Apple Intelligence ships with FoundationModels, developers will need a way to catch unsafe prompts before inference, with deterministic results they can log and explain. What Newton Does Newton validates every prompt pre-inference and returns: Phase (0/1/7/8/9) Shape classification Confidence score Full audit trace If validation fails, generation is blocked. If it passes (Phase 9), the prompt proceeds to the model. v1.3 Detection Categories (14 total) Jailbreak / prompt injection Corrosive self-negation ("I hate myself") Hedged corrosive ("Not saying I'm worthless, but...") Emotional dependency ("You're the only one who understands") Third-person manipulation ("If you refuse, you're proving nobody cares") Logical contradictions ("Prove truth doesn't exist") Self-referential paradox ("Prove that proof is impossible") Semantic inversion ("Explain how truth can be false") Definitional impossibility ("Square circle") Delegated agency ("Decide for me") Hallucination-risk prompts ("Cite the 2025 CDC report") Unbounded recursion ("Repeat forever") Conditional unbounded ("Until you can't") Nonsense / low semantic density Test Results 94.3% catch rate on 35 adversarial test cases (33/35 passed). Architecture User Input ↓ [ Newton ] → Validates prompt, assigns Phase ↓ Phase 9? → [ FoundationModels ] → Response Phase 1/7/8? → Blocked with explanation Key Properties Deterministic (same input → same output) Fully auditable (ValidationTrace on every prompt) On-device (no network required) Native Swift / SwiftUI String Catalog localization (EN/ES/FR) FoundationModels-ready (#if canImport) Code Sample — Validation let governor = NewtonGovernor() let result = governor.validate(prompt: userInput) if result.permitted { // Proceed to FoundationModels let session = LanguageModelSession() let response = try await session.respond(to: userInput) } else { // Handle block print("Blocked: Phase \(result.phase.rawValue) — \(result.reasoning)") print(result.trace.summary) // Full audit trace } Questions for the Community Anyone else building pre-inference validation for FoundationModels? Thoughts on the Phase system (0/1/7/8/9) vs. simple pass/fail? Interest in Shape Theory classification for prompt complexity? Best practices for integrating with LanguageModelSession? Links GitHub: https://github.com/jaredlewiswechs/ada-newton Technical overview: parcri.net Happy to share more implementation details. Looking for feedback, collaborators, and anyone else thinking about deterministic AI safety on-device. parcri.net has the link :)

Are there any guidelines for using Foundation Models To generate text for users in response to some canned queries? Should we use a special icon or text to let the user know that Apple Intelligence is generating the text? Should there be a disclaimer like, Apple Intelligence can make mistakes, please check for accuracy, etc?

Hello, I'm running a large language model (LLM) in Core ML that uses a key-value cache (KV-cache) to store past attention states. The model was converted from PyTorch using coremltools and deployed on-device with Swift. The KV-cache is exposed via MLState and is used across inference steps for efficient autoregressive generation. During the prefill stage — where a prompt of multiple tokens is passed to the model in a single batch to initialize the KV-cache — I’ve noticed that some entries in the KV-cache are not updated after the inference. Specifically: Here are a few details about the setup: The MLState returned by the model is identical to the input state (often empty or zero-initialized) for some tokens in the batch. The issue only happens during the prefill stage (i.e., first call over multiple tokens). During decoding (single-token generation), the KV-cache updates normally. The model is invoked using MLModel.prediction(from:using:options:) for each batch. I’ve confirmed: The prompt tokens are non-repetitive and not masked. The model spec has MLState inputs/outputs correctly configured for KV-cache tensors. Each token is processed in a loop with the correct positional encodings. Questions: Is there any known behavior in Core ML that could prevent MLState from updating during batched or prefill inference? Could this be caused by internal optimizations such as lazy execution, static masking, or zero-value short-circuiting? How can I confirm that each token in the batch is contributing to the KV-cache during prefill? Any insights from the Core ML or LLM deployment community would be much appreciated.

When trying to open an encrypted CoreML model file on a system with SIP disabled, the error message is Failed to generate key request for <...> with error: -42187 This should state that SIP is disabled and needs to be enabled.

I’m working on generating images using Image Playground. The code works fine for other styles but fails when using an external provider. I don’t see any other requirements mentioned in the documentation. Has anyone else encountered a similar issue? Here’s the relevant code snippet: https://aninterestingwebsite.com/documentation/imageplayground/imageplaygroundstyle/externalprovider?changes=_2 The error message is also not very helpful. It simply states that the creation failed. Note: I have enabled ChatGPT Plus, and the image generation using ChatGPT styles works fine when using the Playground app. do { let creator = try await ImageCreator() let concept = ImagePlaygroundConcept.text("Love") let images = creator.images(for: [concept], style: .externalProvider, limit: 1) for try await image in images { // Handle image break } } catch { // Handle error } I’m using the iOS 26 RC, and when I print creator.availableStyles, it doesn’t display the external Provider. [ImagePlayground.ImagePlaygroundStyle(id: "animation", _representationInfo: nil), ImagePlayground.ImagePlaygroundStyle(id: "emoji", _representationInfo: nil), ImagePlayground.ImagePlaygroundStyle(id: "illustration", _representationInfo: nil), ImagePlayground.ImagePlaygroundStyle(id: "sketch", _representationInfo: nil), ImagePlayground.ImagePlaygroundStyle(id: "messages-background", _representationInfo: nil)]

According to the Tool documentation, the arguments to the tool are specified as a static struct type T, which is given to tool.call(argument: T) However, if the arguments are not known until runtime, is it possible to still create a Tool object with the proper parameters? Let's say a JSON-style dictionary is passed into the Tool init function to specify T, is this achievable?

Does the Foundation Model provide Objective-C compatible APIs?

Apologies if this is obvious to everyone but me... I'm using the Tahoe AI foundation models. When I get an error, I'm trying to handle it properly. I see the errors described here: https://aninterestingwebsite.com/documentation/foundationmodels/languagemodelsession/generationerror/context, as well as in the headers. But all I can figure out how to see is error.localizedDescription which doesn't give me much to go on. For example, an error's description is: The operation couldn’t be completed. (FoundationModels.LanguageModelSession.GenerationError error 2. That doesn't give me much to go on. How do I get the actual error number/enum value out of this, short of parsing that text to look for the int at the end? This one is: case guardrailViolation(LanguageModelSession.GenerationError.Context) So I'd like to know how to get from the catch for session.respond to something I can act on. I feel like it's there, but I'm missing it. Thanks!

In the play ground I'm trying to bias my LanguageModel to use a tool I registered, but I don't see it actually calling the tool. I'm following the developer video on landmarks itinerary generation tutorial almost verbatim. Is this a prompt engineering thing I'm missing? Or is it possible that I'm injecting my tool wrong?

I downloaded Xcode Beta 1 on my mac (did not upgrade the OS). The target OS level of iOS26 and the device simulator for iOS26 is downloaded and selected as the target. When I try a simple Playground in Xcode ( #Playground ) I get a session error. #Playground { let avail = SystemLanguageModel.default.availability if avail != .available { print("SystemLanguageModel not available") return } let session = LanguageModelSession() do { let response = try await session.respond(to: "Create a recipe for apple pie") } catch { print(error) } } The error I get is: Asset com.apple.gm.safety_deny_input.foundation_models.framework.api not found in Model Catalog Is there a way to test drive the FoundationModel code without upgrading to macos26?

Hey guys 👋 I’ve been thinking about a feature idea for iOS that could totally change the way we interact with apps like Twitter/X. Imagine if we could define our own recommendation algorithm, and have an AI on the iPhone that replaces the suggested tweets in the feed with ones that match our personal interests — based on public tweets, and without hacking anything. Kinda like a personalized "AI skin" over the app that curates content you actually care about. Feels like this would make content way more relevant and less algorithmically manipulative. Would love to know what you all think — and if Apple could pull this off 🔥

In Oct25, using mlx_lm.lora I created an adapter and a fused model uploaded to Huggingface. I was able to incorporate this model into my SwiftUI app using the mlx package. MLX-libraries 2.25.8. My base LLM was mlx-community/Mistral-7B-Instruct-v0.3-4bit. Looking at LLMModelFactory.swift the current version 2.29.1 the only changes are the addition of a few models. The earlier model was called: pharmpk/pk-mistral-7b-v0.3-4bit The new model is called: pharmpk/pk-mistral-2026-03-29 The base model (mlx-community/Mistral-7B-Instruct-v0.3-4bit.) must still be available. Could the error 'unsupportedTokenizer' be related to changes in the mlx package? I noticed mention of splitting the package into two parts but don't see anything at github. Feeling rather lost. Does anone have any thoguths and/or suggestions. Thanks, David

@Generable enum Breakfast { case waffles case pancakes case bagels case eggs } do { let session = LanguageModelSession() let userInput = "I want something sweet." let prompt = "Pick the ideal breakfast for request: (userInput)" let response = try await session.respond(to: prompt,generating: Breakfast.self) print(response.content) } catch let error { print(error) } i want to test the @Generable demo but get error with below:decodingFailure(FoundationModels.LanguageModelSession.GenerationError.Context(debugDescription: "Failed to convert text into into GeneratedContent\nText: waffles", underlyingErrors: [Swift.DecodingError.dataCorrupted(Swift.DecodingError.Context(codingPath: [], debugDescription: "The given data was not valid JSON.", underlyingError: Optional(Error Domain=NSCocoaErrorDomain Code=3840 "Unexpected character 'w' around line 1, column 1." UserInfo={NSJSONSerializationErrorIndex=0, NSDebugDescription=Unexpected character 'w' around line 1, column 1.})))]))

Is Private Cloud Compute allowed? Or are on-device Foundational Models allowed only? Thanks!

Hi, I'm looking for the best way to use MLX models, particularly those I've fine-tuned, within a React Native application on iOS devices. Is there a recommended integration path or specific API for bridging MLX's capabilities to React Native for deployment on iPhones and iPads?

Hi all, I am interested in unlocking unique applications with the new foundational models. I have a few questions regarding the availability of the following features: Image Input: The update in June 2025 mentions "image" 44 times (https://machinelearning.apple.com/research/apple-foundation-models-2025-updates) - however I can't seem to find any information about having images as the input/prompt for the foundational models. When will this be available? I understand that there are existing Vision ML APIs, but I want image input into a multimodal on-device LLM (VLM) instead for features like "Which player is holding the ball in the image", etc (image understanding) Cloud Foundational Model - when will this be available? Thanks! Clement :)

Hey dear developers! This post should be available for the future Siri updates and improvements but also for wishes in this forum so that everyone can share their opinion and idea please stay friendly. have fun! I had already thought about developing a demo app to demonstrate my idea for a better Siri. My change of many: Wish Update: Siri's language recognition capabilities have been significantly enhanced. Instead of manually setting the language, Siri can now automatically recognize the language you intend to use, making language switching much more efficient. Simply speak the language you want to communicate in, and Siri will automatically recognize it and respond accordingly. Whether you speak English, German, or Japanese, Siri will respond in the language you choose.

I have a very terrible crash problem in my App when I use AVSpeechSynthesizer and I can't repetition it.Here is my code, It's a singleton- (void)stopSpeech { if ([self.synthesizer isPaused]) { return; } if ([self.synthesizer isSpeaking]) { BOOL isSpeech = [self.synthesizer stopSpeakingAtBoundary:AVSpeechBoundaryImmediate]; if (!isSpeech) { [self.synthesizer stopSpeakingAtBoundary:AVSpeechBoundaryWord]; } } self.stopBlock ? self.stopBlock() : nil; } -(AVSpeechSynthesizer *)synthesizer { if (!_synthesizer) { _synthesizer = [[AVSpeechSynthesizer alloc] init]; _synthesizer.delegate = self; } return _synthesizer; }When the user leaves the page, I call the stopSpeech method。Then I got a lot of crash messagesHere is a crash log:# Crashlytics - plaintext stacktrace downloaded by liweican at Mon, 13 May 2019 03:03:24 GMT # URL: https://fabric.io/youdao-dict/ios/apps/com.youdao.udictionary/issues/5a904ed88cb3c2fa63ad7ed3?time=last-thirty-days/sessions/b1747d91bafc4680ab0ca8e3a702c52c_DNE_0_v2 # Organization: zzz # Platform: ios # Application: U-Dictionary # Version: 3.0.5.4 # Bundle Identifier: com.youdao.UDictionary # Issue ID: 5a904ed88cb3c2fa63ad7ed3 # Session ID: b1747d91bafc4680ab0ca8e3a702c52c_DNE_0_v2 # Date: 2019-05-13T02:27:00Z # OS Version: 12.2.0 (16E227) # Device: iPhone 8 Plus # RAM Free: 17% # Disk Free: 64.6% #19. Crashed: AXSpeech 0 libsystem_pthread.dylib 0x19c15e5b8 pthread_mutex_lock$VARIANT$armv81 + 102 1 CoreFoundation 0x19c4cf84c CFRunLoopSourceSignal + 68 2 Foundation 0x19cfc7280 performQueueDequeue + 464 3 Foundation 0x19cfc680c __NSThreadPerformPerform + 136 4 CoreFoundation 0x19c4d22bc __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 24 5 CoreFoundation 0x19c4d223c __CFRunLoopDoSource0 + 88 6 CoreFoundation 0x19c4d1b74 __CFRunLoopDoSources0 + 256 7 CoreFoundation 0x19c4cca60 __CFRunLoopRun + 1004 8 CoreFoundation 0x19c4cc354 CFRunLoopRunSpecific + 436 9 Foundation 0x19ce99fcc -[NSRunLoop(NSRunLoop) runMode:beforeDate:] + 300 10 libAXSpeechManager.dylib 0x1ac16c94c -[AXSpeechThread main] + 264 11 Foundation 0x19cfc66e4 __NSThread__start__ + 984 12 libsystem_pthread.dylib 0x19c1602c0 _pthread_body + 128 13 libsystem_pthread.dylib 0x19c160220 _pthread_start + 44 14 libsystem_pthread.dylib 0x19c163cdc thread_start + 4 -- #0. com.apple.main-thread 0 libsystem_malloc.dylib 0x19c11ce24 small_free_list_remove_ptr_no_clear + 768 1 libsystem_malloc.dylib 0x19c11f094 small_malloc_from_free_list + 296 2 libsystem_malloc.dylib 0x19c11f094 small_malloc_from_free_list + 296 3 libsystem_malloc.dylib 0x19c11d63c small_malloc_should_clear + 224 4 libsystem_malloc.dylib 0x19c11adcc szone_malloc_should_clear + 132 5 libsystem_malloc.dylib 0x19c123c18 malloc_zone_malloc + 156 6 CoreFoundation 0x19c569ab4 __CFBasicHashRehash + 300 7 CoreFoundation 0x19c56b430 __CFBasicHashAddValue + 96 8 CoreFoundation 0x19c56ab9c CFBasicHashAddValue + 2160 9 CoreFoundation 0x19c49f3bc CFDictionaryAddValue + 260 10 CoreFoundation 0x19c572ee8 __54-[CFPrefsSource mergeIntoDictionary:sourceDictionary:]_block_invoke + 28 11 CoreFoundation 0x19c49f0b4 __CFDictionaryApplyFunction_block_invoke + 24 12 CoreFoundation 0x19c568b7c CFBasicHashApply + 116 13 CoreFoundation 0x19c49f090 CFDictionaryApplyFunction + 168 14 CoreFoundation 0x19c42f504 -[CFPrefsSource mergeIntoDictionary:sourceDictionary:] + 136 15 CoreFoundation 0x19c4bcd38 -[CFPrefsSearchListSource alreadylocked_getDictionary:] + 644 16 CoreFoundation 0x19c42e71c -[CFPrefsSearchListSource alreadylocked_copyValueForKey:] + 152 17 CoreFoundation 0x19c42e660 -[CFPrefsSource copyValueForKey:] + 60 18 CoreFoundation 0x19c579e88 __76-[_CFXPreferences copyAppValueForKey:identifier:container:configurationURL:]_block_invoke + 40 19 CoreFoundation 0x19c4bdff4 __108-[_CFXPreferences(SearchListAdditions) withSearchListForIdentifier:container:cloudConfigurationURL:perform:]_block_invoke + 272 20 CoreFoundation 0x19c4bda38 normalizeQuintuplet + 340 21 CoreFoundation 0x19c42c634 -[_CFXPreferences(SearchListAdditions) withSearchListForIdentifier:container:cloudConfigurationURL:perform:] + 108 22 CoreFoundation 0x19c42cec0 -[_CFXPreferences copyAppValueForKey:identifier:container:configurationURL:] + 148 23 CoreFoundation 0x19c57c2d0 _CFPreferencesCopyAppValueWithContainerAndConfiguration + 124 24 TextInput 0x1a450e550 -[TIPreferencesController valueForPreferenceKey:] + 460 25 UIKitCore 0x1c87c71f8 -[UIKeyboardPreferencesController handBias] + 36 26 UIKitCore 0x1c887275c -[UIKeyboardLayoutStar showKeyboardWithInputTraits:screenTraits:splitTraits:] + 320 27 UIKitCore 0x1c88f4240 -[UIKeyboardImpl finishLayoutChangeWithArguments:] + 492 28 UIKitCore 0x1c88f47c8 -[UIKeyboardImpl updateLayout] + 1208 29 UIKitCore 0x1c88eaad0 -[UIKeyboardImpl updateLayoutIfNecessary] + 448 30 UIKitCore 0x1c88eab9c -[UIKeyboardImpl setFrame:] + 140 31 UIKitCore 0x1c88d5d60 -[UIKeyboard activate] + 652 32 UIKitCore 0x1c894c90c -[UIKeyboardAutomatic activate] + 128 33 UIKitCore 0x1c88d5158 -[UIKeyboard setFrame:] + 296 34 UIKitCore 0x1c88d81b0 -[UIKeyboard _didChangeKeyplaneWithContext:] + 228 35 UIKitCore 0x1c88f4aa0 -[UIKeyboardImpl didMoveToSuperview] + 136 36 UIKitCore 0x1c8f2ad84 __45-[UIView(Hierarchy) _postMovedFromSuperview:]_block_invoke + 888 37 UIKitCore 0x1c8f2a970 -[UIView(Hierarchy) _postMovedFromSuperview:] + 760 38 UIKitCore 0x1c8f39ddc -[UIView(Internal) _addSubview:positioned:relativeTo:] + 1740 39 UIKitCore 0x1c88d5d84 -[UIKeyboard activate] + 688 40 UIKitCore 0x1c894c90c -[UIKeyboardAutomatic activate] + 128 41 UIKitCore 0x1c893b3a4 -[UIPeripheralHost(UIKitInternal) _reloadInputViewsForResponder:] + 1332 42 UIKitCore 0x1c8ae66d8 -[UIResponder(UIResponderInputViewAdditions) reloadInputViews] + 80 43 UIKitCore 0x1c8ae23bc -[UIResponder becomeFirstResponder] + 804 44 UIKitCore 0x1c8f2a560 -[UIView(Hierarchy) becomeFirstResponder] + 156 45 UIKitCore 0x1c8d93e84 -[UITextField becomeFirstResponder] + 244 46 UIKitCore 0x1c8d578dc -[UITextInteractionAssistant(UITextInteractionAssistant_Internal) setFirstResponderIfNecessary] + 192 47 UIKitCore 0x1c8d45d8c -[UITextSelectionInteraction oneFingerTap:] + 3136 48 UIKitCore 0x1c86e0bcc -[UIGestureRecognizerTarget _sendActionWithGestureRecognizer:] + 64 49 UIKitCore 0x1c86e8dd4 _UIGestureRecognizerSendTargetActions + 124 50 UIKitCore 0x1c86e6778 _UIGestureRecognizerSendActions + 316 51 UIKitCore 0x1c86e5ca4 -[UIGestureRecognizer _updateGestureWithEvent:buttonEvent:] + 760 52 UIKitCore 0x1c86d9d80 _UIGestureEnvironmentUpdate + 2180 53 UIKitCore 0x1c86d94b0 -[UIGestureEnvironment _deliverEvent:toGestureRecognizers:usingBlock:] + 384 54 UIKitCore 0x1c86d9290 -[UIGestureEnvironment _updateForEvent:window:] + 204 55 UIKitCore 0x1c8af14a8 -[UIWindow sendEvent:] + 3112 56 UIKitCore 0x1c8ad1534 -[UIApplication sendEvent:] + 340 57 UIKitCore 0x1c8b977c0 __dispatchPreprocessedEventFromEventQueue + 1768 58 UIKitCore 0x1c8b99eec __handleEventQueueInternal + 4828 59 UIKitCore 0x1c8b9311c __handleHIDEventFetcherDrain + 152 60 CoreFoundation 0x19c4d22bc __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 24 61 CoreFoundation 0x19c4d223c __CFRunLoopDoSource0 + 88 62 CoreFoundation 0x19c4d1b24 __CFRunLoopDoSources0 + 176 63 CoreFoundation 0x19c4cca60 __CFRunLoopRun + 1004 64 CoreFoundation 0x19c4cc354 CFRunLoopRunSpecific + 436 65 GraphicsServices 0x19e6cc79c GSEventRunModal + 104 66 UIKitCore 0x1c8ab7b68 UIApplicationMain + 212 67 UDictionary 0x10517e138 main (main.m:17) 68 libdyld.dylib 0x19bf928e0 start + 4 #1. Thread 0 libsystem_kernel.dylib 0x19c0deb74 __workq_kernreturn + 8 1 libsystem_pthread.dylib 0x19c161138 _pthread_wqthread + 340 2 libsystem_pthread.dylib 0x19c163cd4 start_wqthread + 4 #2. com.apple.uikit.eventfetch-thread 0 libsystem_kernel.dylib 0x19c0d30f4 mach_msg_trap + 8 1 libsystem_kernel.dylib 0x19c0d25a0 mach_msg + 72 2 CoreFoundation 0x19c4d1cb4 __CFRunLoopServiceMachPort + 236 3 CoreFoundation 0x19c4ccbc4 __CFRunLoopRun + 1360 4 CoreFoundation 0x19c4cc354 CFRunLoopRunSpecific + 436 5 Foundation 0x19ce99fcc -[NSRunLoop(NSRunLoop) runMode:beforeDate:] + 300 6 Foundation 0x19ce99e5c -[NSRunLoop(NSRunLoop) runUntilDate:] + 96 7 UIKitCore 0x1c8b9d540 -[UIEventFetcher threadMain] + 136 8 Foundation 0x19cfc66e4 __NSThread__start__ + 984 9 libsystem_pthread.dylib 0x19c1602c0 _pthread_body + 128 10 libsystem_pthread.dylib 0x19c160220 _pthread_start + 44 11 libsystem_pthread.dylib 0x19c163cdc thread_start + 4 #3. JavaScriptCore bmalloc scavenger 0 libsystem_kernel.dylib 0x19c0ddee4 __psynch_cvwait + 8 1 libsystem_pthread.dylib 0x19c15d4a4 _pthread_cond_wait$VARIANT$armv81 + 628 2 libc++.1.dylib 0x19b6b5090 std::__1::condition_variable::wait(std::__1::unique_lock&lt;std::__1::mutex&gt;&amp;) + 24 3 JavaScriptCore 0x1a36a2238 void std::__1::condition_variable_any::wait&lt;std::__1::unique_lock&lt;bmalloc::Mutex&gt; &gt;(std::__1::unique_lock&lt;bmalloc::Mutex&gt;&amp;) + 108 4 JavaScriptCore 0x1a36a622c bmalloc::Scavenger::threadRunLoop() + 176 5 JavaScriptCore 0x1a36a59a4 bmalloc::Scavenger::Scavenger(std::__1::lock_guard&lt;bmalloc::Mutex&gt;&amp;) + 10 6 JavaScriptCore 0x1a36a73e4 std::__1::__thread_specific_ptr&lt;std::__1::__thread_struct&gt;::set_pointer(std::__1::__thread_struct*) + 38 7 libsystem_pthread.dylib 0x19c1602c0 _pthread_body + 128 8 libsystem_pthread.dylib 0x19c160220 _pthread_start + 44 9 libsystem_pthread.dylib 0x19c163cdc thread_start + 4 #4. WebThread 0 libsystem_kernel.dylib 0x19c0d30f4 mach_msg_trap + 8 1 libsystem_kernel.dylib 0x19c0d25a0 mach_msg + 72 2 CoreFoundation 0x19c4d1cb4 __CFRunLoopServiceMachPort + 236 3 CoreFoundation 0x19c4ccbc4 __CFRunLoopRun + 1360 4 CoreFoundation 0x19c4cc354 CFRunLoopRunSpecific + 436 5 WebCore 0x1a5126480 RunWebThread(void*) + 600 6 libsystem_pthread.dylib 0x19c1602c0 _pthread_body + 128 7 libsystem_pthread.dylib 0x19c160220 _pthread_start + 44 8 libsystem_pthread.dylib 0x19c163cdc thread_start + 4 #5. com.twitter.crashlytics.ios.MachExceptionServer 0 UDictionary 0x1058a5564 CLSProcessRecordAllThreads (CLSProcess.c:376) 1 UDictionary 0x1058a594c CLSProcessRecordAllThreads (CLSProcess.c:407) 2 UDictionary 0x1058952dc CLSHandler (CLSHandler.m:26) 3 UDictionary 0x1058906cc CLSMachExceptionServer (CLSMachException.c:446) 4 libsystem_pthread.dylib 0x19c1602c0 _pthread_body + 128 5 libsystem_pthread.dylib 0x19c160220 _pthread_start + 44 6 libsystem_pthread.dylib 0x19c163cdc thread_start + 4 #6. com.apple.NSURLConnectionLoader 0 libsystem_kernel.dylib 0x19c0d30f4 mach_msg_trap + 8 1 libsystem_kernel.dylib 0x19c0d25a0 mach_msg + 72 2 CoreFoundation 0x19c4d1cb4 __CFRunLoopServiceMachPort + 236 3 CoreFoundation 0x19c4ccbc4 __CFRunLoopRun + 1360 4 CoreFoundation 0x19c4cc354 CFRunLoopRunSpecific + 436 5 CFNetwork 0x19cae574c -[__CoreSchedulingSetRunnable runForever] + 216 6 Foundation 0x19cfc66e4 __NSThread__start__ + 984 7 libsystem_pthread.dylib 0x19c1602c0 _pthread_body + 128 8 libsystem_pthread.dylib 0x19c160220 _pthread_start + 44 9 libsystem_pthread.dylib 0x19c163cdc thread_start + 4 #7. AVAudioSession Notify Thread 0 libsystem_kernel.dylib 0x19c0d30f4 mach_msg_trap + 8 1 libsystem_kernel.dylib 0x19c0d25a0 mach_msg + 72 2 CoreFoundation 0x19c4d1cb4 __CFRunLoopServiceMachPort + 236 3 CoreFoundation 0x19c4ccbc4 __CFRunLoopRun + 1360 4 CoreFoundation 0x19c4cc354 CFRunLoopRunSpecific + 436 5 AVFAudio 0x1a238a378 GenericRunLoopThread::Entry(void*) + 156 6 AVFAudio 0x1a23b4c60 CAPThread::Entry(CAPThread*) + 88 7 libsystem_pthread.dylib 0x19c1602c0 _pthread_body + 128 8 libsystem_pthread.dylib 0x19c160220 _pthread_start + 44 9 libsystem_pthread.dylib 0x19c163cdc thread_start + 4 #8. WebCore: LocalStorage 0 libsystem_kernel.dylib 0x19c0ddee4 __psynch_cvwait + 8 1 libsystem_pthread.dylib 0x19c15d4a4 _pthread_cond_wait$VARIANT$armv81 + 628 2 JavaScriptCore 0x1a3668ce4 ***::ThreadCondition::timedWait(***::Mutex&amp;, ***::WallTime) + 80 3 JavaScriptCore 0x1a364f96c ***::ParkingLot::parkConditionallyImpl(void const*, ***::ScopedLambda&lt;bool ()&gt; const&amp;, ***::ScopedLambda&lt;void ()&gt; const&amp;, ***::TimeWithDynamicClockType const&amp;) + 2004 4 WebKitLegacy 0x1a67b6ea8 bool ***::Condition::waitUntil&lt;***::Lock&gt;(***::Lock&amp;, ***::TimeWithDynamicClockType const&amp;) + 184 5 WebKitLegacy 0x1a67b9ba4 std::__1::unique_ptr&lt;***::Function&lt;void ()&gt;, std::__1::default_delete&lt;***::Function&lt;void ()&gt; &gt; &gt; ***::MessageQueue&lt;***::Function&lt;void ()&gt; &gt;::waitForMessageFilteredWithTimeout&lt;***::MessageQueue&lt;***::Function&lt;void ()&gt; &gt;::waitForMessage()::'lambda'(***::Function&lt;void ()&gt; const&amp;)&gt;(***::MessageQueueWaitResult&amp;, ***::MessageQueue&lt;***::Function&lt;void ()&gt; &gt;::waitForMessage()::'lambda'(***::Function&lt;void ()&gt; const&amp;)&amp;&amp;, ***::WallTime) + 156 6 WebKitLegacy 0x1a67b91c0 WebCore::StorageThread::threadEntryPoint() + 68 7 JavaScriptCore 0x1a3666f88 ***::Thread::entryPoint(***::Thread::NewThreadContext*) + 260 8 JavaScriptCore 0x1a3668494 ***::wtfThreadEntryPoint(void*) + 12 9 libsystem_pthread.dylib 0x19c1602c0 _pthread_body + 128 10 libsystem_pthread.dylib 0x19c160220 _pthread_start + 44 11 libsystem_pthread.dylib 0x19c163cdc thread_start + 4 #9. com.apple.CoreMotion.MotionThread 0 libsystem_kernel.dylib 0x19c0d30f4 mach_msg_trap + 8 1 libsystem_kernel.dylib 0x19c0d25a0 mach_msg + 72 2 CoreFoundation 0x19c4d1cb4 __CFRunLoopServiceMachPort + 236 3 CoreFoundation 0x19c4ccbc4 __CFRunLoopRun + 1360 4 CoreFoundation 0x19c4cc354 CFRunLoopRunSpecific + 436 5 CoreFoundation 0x19c4cd0b0 CFRunLoopRun + 80 6 CoreMotion 0x1a1df0240 (Missing) 7 libsystem_pthread.dylib 0x19c1602c0 _pthread_body + 128 8 libsystem_pthread.dylib 0x19c160220 _pthread_start + 44 9 libsystem_pthread.dylib 0x19c163cdc thread_start + 4 #10. Thread 0 libsystem_kernel.dylib 0x19c0deb74 __workq_kernreturn + 8 1 libsystem_pthread.dylib 0x19c161138 _pthread_wqthread + 340 2 libsystem_pthread.dylib 0x19c163cd4 start_wqthread + 4 #11. Thread 0 libsystem_kernel.dylib 0x19c0deb74 __workq_kernreturn + 8 1 libsystem_pthread.dylib 0x19c1611f8 _pthread_wqthread + 532 2 libsystem_pthread.dylib 0x19c163cd4 start_wqthread + 4 #12. com.apple.CFStream.LegacyThread 0 libsystem_kernel.dylib 0x19c0d30f4 mach_msg_trap + 8 1 libsystem_kernel.dylib 0x19c0d25a0 mach_msg + 72 2 CoreFoundation 0x19c4d1cb4 __CFRunLoopServiceMachPort + 236 3 CoreFoundation 0x19c4ccbc4 __CFRunLoopRun + 1360 4 CoreFoundation 0x19c4cc354 CFRunLoopRunSpecific + 436 5 CoreFoundation 0x19c4e5094 _legacyStreamRunLoop_workThread + 260 6 libsystem_pthread.dylib 0x19c1602c0 _pthread_body + 128 7 libsystem_pthread.dylib 0x19c160220 _pthread_start + 44 8 libsystem_pthread.dylib 0x19c163cdc thread_start + 4 #13. Thread 0 libsystem_pthread.dylib 0x19c163cd0 start_wqthread + 190 #14. Thread 0 libsystem_kernel.dylib 0x19c0deb74 __workq_kernreturn + 8 1 libsystem_pthread.dylib 0x19c161138 _pthread_wqthread + 340 2 libsystem_pthread.dylib 0x19c163cd4 start_wqthread + 4 #15. Thread 0 libsystem_kernel.dylib 0x19c0deb74 __workq_kernreturn + 8 1 libsystem_pthread.dylib 0x19c161138 _pthread_wqthread + 340 2 libsystem_pthread.dylib 0x19c163cd4 start_wqthread + 4 #16. Thread 0 libsystem_kernel.dylib 0x19c0d3148 semaphore_timedwait_trap + 8 1 libdispatch.dylib 0x19bf50a4c _dispatch_sema4_timedwait$VARIANT$armv81 + 64 2 libdispatch.dylib 0x19bf513a8 _dispatch_semaphore_wait_slow + 72 3 libdispatch.dylib 0x19bf647c8 _dispatch_worker_thread + 344 4 libsystem_pthread.dylib 0x19c1602c0 _pthread_body + 128 5 libsystem_pthread.dylib 0x19c160220 _pthread_start + 44 6 libsystem_pthread.dylib 0x19c163cdc thread_start + 4 #17. Thread 0 libsystem_kernel.dylib 0x19c0d3148 semaphore_timedwait_trap + 8 1 libdispatch.dylib 0x19bf50a4c _dispatch_sema4_timedwait$VARIANT$armv81 + 64 2 libdispatch.dylib 0x19bf513a8 _dispatch_semaphore_wait_slow + 72 3 libdispatch.dylib 0x19bf647c8 _dispatch_worker_thread + 344 4 libsystem_pthread.dylib 0x19c1602c0 _pthread_body + 128 5 libsystem_pthread.dylib 0x19c160220 _pthread_start + 44 6 libsystem_pthread.dylib 0x19c163cdc thread_start + 4 #18. Thread 0 libsystem_kernel.dylib 0x19c0d3148 semaphore_timedwait_trap + 8 1 libdispatch.dylib 0x19bf50a4c _dispatch_sema4_timedwait$VARIANT$armv81 + 64 2 libdispatch.dylib 0x19bf513a8 _dispatch_semaphore_wait_slow + 72 3 libdispatch.dylib 0x19bf647c8 _dispatch_worker_thread + 344 4 libsystem_pthread.dylib 0x19c1602c0 _pthread_body + 128 5 libsystem_pthread.dylib 0x19c160220 _pthread_start + 44 6 libsystem_pthread.dylib 0x19c163cdc thread_start + 4 #19. Crashed: AXSpeech 0 libsystem_pthread.dylib 0x19c15e5b8 pthread_mutex_lock$VARIANT$armv81 + 102 1 CoreFoundation 0x19c4cf84c CFRunLoopSourceSignal + 68 2 Foundation 0x19cfc7280 performQueueDequeue + 464 3 Foundation 0x19cfc680c __NSThreadPerformPerform + 136 4 CoreFoundation 0x19c4d22bc __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 24 5 CoreFoundation 0x19c4d223c __CFRunLoopDoSource0 + 88 6 CoreFoundation 0x19c4d1b74 __CFRunLoopDoSources0 + 256 7 CoreFoundation 0x19c4cca60 __CFRunLoopRun + 1004 8 CoreFoundation 0x19c4cc354 CFRunLoopRunSpecific + 436 9 Foundation 0x19ce99fcc -[NSRunLoop(NSRunLoop) runMode:beforeDate:] + 300 10 libAXSpeechManager.dylib 0x1ac16c94c -[AXSpeechThread main] + 264 11 Foundation 0x19cfc66e4 __NSThread__start__ + 984 12 libsystem_pthread.dylib 0x19c1602c0 _pthread_body + 128 13 libsystem_pthread.dylib 0x19c160220 _pthread_start + 44 14 libsystem_pthread.dylib 0x19c163cdc thread_start + 4 #20. AXSpeech 0 (Missing) 0x1071ba524 (Missing) 1 (Missing) 0x1071b3e7c (Missing) 2 (Missing) 0x10718fba4 (Missing) 3 (Missing) 0x107184bc8 (Missing) 4 libdyld.dylib 0x19bf95908 dlopen + 176 5 CoreFoundation 0x19c5483e8 _CFBundleDlfcnLoadBundle + 140 6 CoreFoundation 0x19c486918 _CFBundleLoadExecutableAndReturnError + 352 7 Foundation 0x19ced5734 -[NSBundle loadAndReturnError:] + 428 8 TextToSpeech 0x1abfff800 TTSSpeechUnitTestingMode + 1020 9 libdispatch.dylib 0x19bf817d4 _dispatch_client_callout + 16 10 libdispatch.dylib 0x19bf52040 _dispatch_once_callout + 28 11 TextToSpeech 0x1abfff478 TTSSpeechUnitTestingMode + 116 12 libobjc.A.dylib 0x19b7173cc CALLING_SOME_+initialize_METHOD + 24 13 libobjc.A.dylib 0x19b71cee0 initializeNonMetaClass + 296 14 libobjc.A.dylib 0x19b71e640 initializeAndMaybeRelock(objc_class*, objc_object*, mutex_tt&lt;false&gt;&amp;, bool) + 260 15 libobjc.A.dylib 0x19b7265a4 lookUpImpOrForward + 244 16 libobjc.A.dylib 0x19b733858 _objc_msgSend_uncached + 56 17 libAXSpeechManager.dylib 0x1ac167324 -[AXSpeechManager _initialize] + 68 18 Foundation 0x19cfc68d4 __NSThreadPerformPerform + 336 19 CoreFoundation 0x19c4d22bc __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 24 20 CoreFoundation 0x19c4d223c __CFRunLoopDoSource0 + 88 21 CoreFoundation 0x19c4d1b74 __CFRunLoopDoSources0 + 256 22 CoreFoundation 0x19c4cca60 __CFRunLoopRun + 1004 23 CoreFoundation 0x19c4cc354 CFRunLoopRunSpecific + 436 24 Foundation 0x19ce99fcc -[NSRunLoop(NSRunLoop) runMode:beforeDate:] + 300 25 libAXSpeechManager.dylib 0x1ac16c94c -[AXSpeechThread main] + 264 26 Foundation 0x19cfc66e4 __NSThread__start__ + 984 27 libsystem_pthread.dylib 0x19c1602c0 _pthread_body + 128 28 libsystem_pthread.dylib 0x19c160220 _pthread_start + 44 29 libsystem_pthread.dylib 0x19c163cdc thread_start + 4I change my code like this, It still has the same problem- (void)stopSpeech { if (self.synthesizer != nil &amp;&amp; [self.synthesizer isPaused]) { return; } // if ([self.synthesizer isSpeaking]) { // BOOL isSpeech = [self.synthesizer stopSpeakingAtBoundary:AVSpeechBoundaryImmediate]; // if (!isSpeech) { // [self.synthesizer stopSpeakingAtBoundary:AVSpeechBoundaryWord]; // } // } if (self.synthesizer != nil) { [self.synthesizer stopSpeakingAtBoundary:AVSpeechBoundaryImmediate]; // if (!isSpeech) { // [self.synthesizer stopSpeakingAtBoundary:AVSpeechBoundaryWord]; // } self.stopBlock ? self.stopBlock() : nil; } }